Fire-Forming Brass and Annealing

Ganderite

Ganderite

CGN Ultra frequent flyer
Rating - 99.7%
355   1   0
Location
Farm south of North Bay
I am sizing 308 Lapua brass into 260Rem. I do this by running the case through a 7-08 die and then a 260Rem die. No failures in this step.

Then I anneal the cases.

The next step is to fire the cases in a 260Rem Ackley chamber, which blows out the shoulder, making for more capacity.

Should I anneal again??

Or should have I skipped annealing, fire-formed and then annealed?
 
Ganderite said:
I am sizing 308 Lapua brass into 260Rem. I do this by running the case through a 7-08 die and then a 260Rem die. No failures in this step.

Then I anneal the cases.

The next step is to fire the cases in a 260Rem Ackley chamber, which blows out the shoulder, making for more capacity.

Should I anneal again??

Or should have I skipped annealing, fire-formed and then annealed?
Click to expand...

I am still learning a lot about this process, so I may be off, but....

When you run the brass through the dies, it work-hardens the brass and stiffins it up. Work it enough and it can crack and fail. When you anneal it, you re-align the molecules in the brass and softens it up again, making it more malleable. I apologize if this is already common knowledge to you.

Personally, my thoughts are that having the brass as malleable as possible for each of those steps would be a good thing. If it were me, I might even consider annealing before doing the first resizing so that I had a known starting point.

I think once you fire formed, you can treat it like any other brass and reloading on the schedule for annealing you are comfortable with.

This is just my $0.02. I could be very wrong, but this is what I would do with my limited understanding.
 
Ganderite said:
I am sizing 308 Lapua brass into 260Rem. I do this by running the case through a 7-08 die and then a 260Rem die. No failures in this step.

Then I anneal the cases.

The next step is to fire the cases in a 260Rem Ackley chamber, which blows out the shoulder, making for more capacity.

Should I anneal again??

Or should have I skipped annealing, fire-formed and then annealed?
Click to expand...
Absolutely 👍 Also anneal before you size the cases down . There is NO DOWNSIDE to annealing every time Only GOOD 😉 meaning longer life and more consistent neck tension .
 
This is a good post, and appreciated. I’m in a steep learning curve right now with learning 280 Ross, and it’s my first off the path cartridge. I annealed once and have been finding out the hard way that more is better. Lots of inconsistency with case capacity and neck tension. But it’s getting better.
 
  • Like
Reactions: DGY
If your annealing system is easy to do then after each step is ideal. Otherwise I would personally wait until you’ve done the fireform. I believe that firing the case hardens it a lot more than a couple passes through a die. I have a hydraulic form die for a 30 Gibbs and with new brass I’ve never ruined one but trying once fired stuff I had about 10% failure rate, annealing the once fired fixed that.
 
remington jim said:
Absolutely 👍 Also anneal before you size the cases down . There is NO DOWNSIDE to annealing every time Only GOOD 😉 meaning longer life and more consistent neck tension .
Click to expand...
There is no "downside" as long as the heat doesn't go too high, but if it's right, all is good.

I have an old friend who anneals after every shot. He claims it gives him better accuracy.

He can certainly shoot his rifles extremely well, so who am I to contradict him?
 
bearhunter said:
There is no "downside" as long as the heat doesn't go too high, but if it's right, all is good.

I have an old friend who anneals after every shot. He claims it gives him better accuracy.

He can certainly shoot his rifles extremely well, so who am I to contradict him?
Click to expand...
THATS why a AMP. Is the BEST a there is . Computer controlled annealing 👍😀
 
Ganderite said:
I am sizing 308 Lapua brass into 260Rem. I do this by running the case through a 7-08 die and then a 260Rem die. No failures in this step.
Click to expand...

Annealing during case forming can provide 3 possible benefits and 1 possible drawback I can think of.

Annealing before/during forming will lower strength of the brass, reducing the effort required.
Annealing before/during forming will increase ductility of the brass, reducing the possibility of failure due to deformation. Failure of this kind is probably more likely when necking up, rather than down.
Annealing after forming will reduce residual stresses in brass, which can lead to stress-corrosion cracking in storage. Contrary to widespread and popular belief, SCC is by far the most common cause of neck cracking in cartridge cases.

Annealing before/during forming may lower strength enough that the shoulder collapses during reforming.

So understanding the benefits and drawback, choose your annealing plan accordingly. If you find reforming takes lots of effort or you are getting splits, anneal before your steps. If you have a history of neck cracks in your reloads, anneal after forming.

Otherwise, avoid the extra work.
 
257hunter said:
What method are you using to prevent the case head from also being annealed if using an oven?
Click to expand...
I anneal the case head as well.

Many folks get all snotty about this, but it works for me. If the case is strong enough to be shot soft as new, returning the metal to "new" condition isn't going to make any difference, with the loads I use.

I also shoot these cases from the same rifle, and keep them separated, and the containers marked for which rifle they're being used in. This way, I can neck resize only, bumping back the shoulders a few thou after annealing, and if needed, maybe trim a few tho, which is seldom.

I have several hundred 30-06, Dominion brass cases, over 50 years old, with well over a hundred reloads on them, and they're still fine.

They get the treatment after 3-4 firings.

Let the flames roar.
 
I just did approx 150 cases from 30/30 to 35/40 Lucas I had a bunch of old Dominion 30/30 cases , first step deprime ...yes once fired brass ?? Then annealed.. then into tumbler for cleaning. once dry through a 32/40 fl die then with a custom expander open to 358 load with 7.5 gr unique and a 180 gr cast bullet go fire ..... de prime and back into the tumbler for cleaning. ....ready for serious loads. ...fun stuff
 
Yup always annual before reforming. With 006 to 8x57 I made a little jig (a block of wood with a hole and a washer at one end, using a drill adapter and a olfa knife, left them almost burr free) to trim the brass down tounder a couple of thousands of the desired oal. Then annual. Some of those I've since made in to 308.
 
My experience with forming 308 Lapua brass to 260AI is that the necks thickened considerably, which then required turning. Also, 308 is about .030" shorter than 260 and 260AI if I remember correctly. Necking down 308 will result in some lengthening, but not a bunch. Then the forming to an AI chamber will again reduce that length.

What I found was best, was to anneal the unmolested parent case prior to any resizing. Then anneal again after the first firing. The cases seemed to 'stabilize' quite well after that. In my case, I necked down to near final size, then turned to give me adequate chamber neck clearance - only just enough, then final size and load. After first fire, anneal, size to fit my neck turning tool mandrel, turned again to desired neck wall thickness, then final size & load.

Brass does funky things when manipulated. I have made some very uneven case mouths from sizing a long way when I haven't annealed enough prior to that effort. And I have seen wonky brass flow, evidenced by repeated neck turning between firing / sizing cycles, just as an experiment. I've left the turning tool unadjusted and have been able to cut parts of the neck each time for several of those cycles. These cuts would only be tenths of a thou, but it did reveal that brass often does not flow uniformly. Anyway, just some anecdotal observations to create brain worming....

I'll stay out of the annealing bit for the most part, but I have found on some occasions that cooking too much - be it temperature or time - can substantially reduce tensile strength to the point where the intended grip on the bullet relaxes enough to allow bullet slip by hand. Definitely not desirable.

Rooster
 
Ganderite said:
I am sizing 308 Lapua brass into 260Rem. I do this by running the case through a 7-08 die and then a 260Rem die. No failures in this step.

Then I anneal the cases.

The next step is to fire the cases in a 260Rem Ackley chamber, which blows out the shoulder, making for more capacity.

Should I anneal again??

Or should have I skipped annealing, fire-formed and then annealed?
Click to expand...
Annealing softens the brass, so in my opinion softer brass should fire form better than hard brass. 🤷‍♂️
 
You must log in or register to reply here.
Back
Top Bottom